One thing about 2E versus older versions of AD&D was how experience points were rewarded. OD&D, B/X, BECMI, 1E AD&D, all had definitive systems for rewarding XP. I always found the 2E system to be much more ambiguous. Yes there were some rules and some optional rules given but there were no real examples given and lots of DM discretion.
I haven't played a lot (read hardly any) of 3rd edition. My understanding is that level progression is much faster than in earlier editions. The first published adventure in Rise of the Runelords, Burnt Offerings, is written for 3rd edition characters to advance from 1st to approximately 4th level. While I haven't been keeping an accurate tally of what XP would have been earned by the current PCs using any of the older systems, it definitely feels a lot faster.
I have been using an "XP Budget" to reward experience points. I know that I want a PC fighter to advance by 2 levels per published adventure (therefore, six adventures = 12 levels). Using fighters as the baseline means that some other classes will advance faster and others slower. Reading through each adventure, I pick 5 or 6 milestones. Each milestone then becomes worth one-fifth or sixth of the required XP to reach the target level for that adventure. If the PCs go off the rails and find new and creative ways to deal with things other than by following the milestones, I can just adapt the milestones.
For example, one of the milestones in the first adventure was rescuing Ameiko from her half-brother, Tsuto. This was one of six milestones I had in the first adventure. I also knew that I wanted a PC fighter to reach 3rd level by the end of the first adventure which requires 4,000 XP. Each milestone is then worth 4,000/6 = 667 XP.
I have also been awarding bonuses based on interesting circumstances. For example, when Toran the thief was caught in a compromising position by Vin Vender with the shop owner's daughter, Toran received bonus XP for extricating himself from the predicament.
I have been using a rule that if a character dies, the new character begins with an XP total equal to 50% of the previous characters XP. This makes the punishment for death equal to about one level at lower levels and maybe two levels at higher level. At lower levels, this penalty can easily be made up with sidequests. At higher levels, it is much less likely to have players die so I don't mind the slightly harsher penalty - at least not yet... we will see how it works if it actually happens.
Hex Stocking Density
5 years ago